This invention relates to a sheet sorting apparatus which comprises a delivery device for delivering sheets one after another, first and second main belts separated at an angle from each other after running through a main superposed section in which the belts hold and carry the delivered sheets, and defining a triangular space therebetween adjoining the main superposed section, first and second auxiliary belts superposed on part of the main belts to form first and second auxiliary superposed sections, respectively, pulley means for guiding all the belts, the pulley means including shape determining pulleys to determine the shape of the space, a separator member rockably supported in the space, the separator member rocking through a predetermined angle to guide the sheets fed from the main superposed section into the space to one of the auxiliary superposed sections corresponding to the rocking direction of the separator member, means for rocking the separator member, and first and second collectors receiving and holding therein the sheets delivered from the first and second auxiliary superposed sections.
The sheets include, for example, data cards, bank notes, etc., which are normally kept in piles. In order to classify or sort these piled sheets according to the kind of information or for regular division, it is necessary that the sheets be picked up one by one and delivered to a conveyor path, subjected to information reading or counting in the middle of the path, and then collected again in piles through diverging courses for each individual kind of information or for each regular lot.
Conventional sheet conveying systems include a belt conveyor system in which the sheets picked up one by one are carried to a predetermined position while they are held between a pair of belts running in contact with each other. Conventional means for shifting the course of the sheets transferred in the belt conveyor system most frequently has the following construction. The conveyor belts are separated in the middle of the conveyor path to define a fan-shaped spread between them. Two pulleys are provided inside the fan-shaped spread between the conveyor belts, and additional belts forming first and second independent paths individually in contact with the spreading conveyor belts are separately arranged on the two pulleys. A separator member which rotates in either direction around an axis parallel to the shafts of the pulleys is disposed in a substantially triangular space defined by the spreading portions of the conveyor belts and the two pulleys. The separator member has triangular lateral faces, and is rotated in the forward or reverse direction in response to a shifting command signal to form a gap between one side of the separator member and the spreading portion of one of the conveyor belts so that the sheets are carried through the gap. Then, the sheets are delivered to the first or second path formed by the belt on one of the pulleys located behind the separator member and the spreading portion of one of the conveyor belts, and are held and carried to the predetermined position.
Conventionally, a rotary solenoid or a reversible motor is used as a driving source for rotating the separator member The rotary solenoid has a function to convert linear motion mechanically to a rotary stroke by the use of a plunger-type solenoid. When using the rotary solenoid, the rotation may be reversed compulsorily by means of a spring or by using a pair of rotary solenoids with the same function with are connected coaxially in opposite direction. In the latter case, one of the solenoids is excited for forward or reverse rotation. When using the reversible motor, the rotary stroke of the separator member is usually fixed by means of an external stopper against which an arm attached to the rotating shaft of the separator member is to abut.
In the prior art sheet sorting apparatus of the aforementioned construction, the means for fixing the rotary stroke of the separator member involves the following drawbacks.
(1) The number of parts used in the apparatus is increased to result in complicated construction and higher cost. Namely, the driving source using the rotary solenoid requires a spring or an additional rotary solenoid for the reversal of rotation, while the one using the reversible motor requires an arm and a stopper for the positioning of the separator member.
(2) The separator member cannot provide adequate high speed response for the reversal of rotation. In the driving source using the spring for the reversal as mentioned in item (1), the spring force acts in one direction only, so that the forward rotation of the separator member requires a great enough force to surpass the spring force, resulting in a reduction of high speed response. In the driving source using the coupled pair of rotary solenoids, the rotating part is longer (about twice) and heavier, so that the moment of inertia is increased. In the case where the reversible motor is used, the arm on the shaft for positioning adds to the weight of the apparatus to increase the moment of inertia. Thus, quick rotation of the separator member is prevented.
(3) In all those shaft driving systems, the force applied to the shaft or the increased weight leads to an increase in the required power source capacity. In the spring-type driving source, in particular, the position of the solenoid cannot be maintained unless the solenoid continues to be supplied with enough electric power to counter the spring force. Accordingly, the solenoid may be heated, and the rotating shaft takes a long time to stop its vibration at the end of the operation. Thus, the separator member cannot be positioned in a short time.
(4) In the driving system using the reversible motor, the separator member is positioned by striking the arm attached to the rotating shaft against the stopper. The higher the operating speed, therefore, the greater the force on the arm at the moment of impact will be. Accordingly, high-speed operation may damage the stopper or arm. Accordingly the stopper and the arm mut be made with a special strong material. Moreover, the vibration caused at the impact will continue for a short time, and the separator member cannot be positioned accurately. As a result, the passage defined by one lateral face of the separator member and the conveyor belt lacks stability, so that the sheets led into the passage will possible run against the vibrating separator member to jam.